This invention relates to a cutting arrangement for a machine.
According to the invention a cutting arrangement includes a pick holder having a bore containing a sleeve within which a shank of a pick is located, with the pick and the sleeve each having heads, the head of the sleeve having an outer abutting surface and an inner abutting surface, the outer abutting surface abuts an abutting surface of the head of the pick and the inner abutting surface abuts an abutting surface of the pick holder, with the abutting surface of the head of the pick having a convex formation which abuts a concave formation on the outer abutting surface of the sleeve.
Preferably the inner abutting surface on the sleeve has a convex formation and the abutting surface of the pick holder has a concave formation, with the convex and concave formations abutting one another.
The abutting surface of the head of the pick and the outer abutting surface of the head of the sleeve may include planar surfaces which abut one another.
The inner abutting surface of the head of the sleeve and the abutting surface of the pick holder may include planar surfaces which abut one another.
The shank of the pick and the bore of the sleeve may include retaining formations for retaining the sleeve and the shank within the pick holder if the head of the pick is severed from the shank. The retaining formations may be step formations.
The shank is preferably rotatable within the sleeve and the sleeve is preferably rotatable within the bore of the pick holder. Thus the sleeve is not an interference fit within the bore of the pick holder, but is a sliding fit within the bore of the pick holder.
The sleeve preferably has a tail which abuts a step in the bore of the pick holder, the tail having an inwardly curved formation which abuts an outwardly curved formation on the step.
The pick is preferably retained within the pick holder by a clip releasably secured to the pick.
According to another aspect of the invention a cutting arrangement includes a pick holder having a bore containing a sleeve within which a shank of a pick is located, with the pick and the sleeve each having heads, the head of the sleeve having an outer abutting surface and an inner abutting surface, the outer abutting surface abuts an abutting surface of the head of the pick, and the inner abutting surface abuts an abutting surface of the pick holder, with the inner abutting surface of the head of the sleeve having an outwardly curved formation and the abutting surface of the pick holder having an inwardly curved formation, with the inwardly and outwardly curved formations abutting one another.
According to another aspect of the invention a cutting arrangement includes a pick and a pick holder, the pick having a head with a shank extending therefrom, the head having an abutting surface which abuts an abutting surface of the pick holder, the abutting surface of the head having a convex formation which abuts a concave formation on the abutting surface of the pick holder.
The abutting surfaces of the pick and the pick holder may include planar surfaces which abut one another.
The shank of the pick and the bore of the pick holder may include retaining formations for retaining the shank within the bore if the head is severed from the shank. The retaining formations may be step formations.
According to another aspect of the invention a cutting arrangement includes a pick holder having a bore containing a sleeve within which the shank of a pick is located, with the shank of the pick and the bore of the sleeve having retaining formations for retaining the sleeve and the shank within the pick holder if the head of the pick is severed from the shank.
According to another aspect of the invention a sleeve includes an outer abutting surface for abutting a head of a pick, and an inner abutting surface for abutting a pick holder, the outer abutting surface having an inwardly curved formation for abutting an outwardly curved formation on the head of the pick.
The inner abutting surface may have an outwardly curved formation for abutting an inwardly curved formation on the pick holder.
The sleeve preferably has a tail which abuts a step in the bore of the pick holder, the tail having an inwardly curved formation for abutting an outwardly curved formation on the step.
According to another aspect of the invention a sleeve includes an outer abutting surface for abutting a head of a pick, and an inner abutting surface for abutting a pick holder, the inner abutting surface having an outwardly curved formation for abutting an inwardly curved formation on the pick holder.
According to another aspect of the invention a pick holder includes an abutting surface with a inwardly curved formation for abutting an outwardly curved formation on a sleeve or a pick.
The pick holder preferably has a step in its bore for abutting a tail of the sleeve, the step having an outwardly curved formation for abutting an inwardly curved formation on the tail.